Q: Convert all .jpg images in directory to .pdf | Debugging ImageMagick I have found multiple posts regarding this issue and everyone is recommending ImageMagick but for me, it doesn't seem to work as intended and I don't see too many docs on their site regarding .jpg->.pdf conversion.
Is there some alternative, preferably CLI tool?
Or can I somehow debug why ImageMagick doesn't work for me? I don't get any errors I just get corrupted files as a result.
My usecase

My os is Windows and
I have 64 .jpg files called 0.jpg, 2.jpg, ... 63.jpg and I would like to merge all those images into one .pdf file.
I have tried these commands:
magick *.jpg out.pdf

convert *.jpg out.pdf

but in both cases, I am unable to open the out.pdf file because it is corrupted. I have noticed that I can only convert 0.jpg file to pdf correctly but when I try to convert any other of my 64 jpg files then as a result I am getting a corrupted .pdf file
For example:
This gives me the correct .pdf:
magick 0.jpg 0.pdf

but this gives me corrupted .pdf:
magick 2.jpg 2.pdf

I assume that this a reason why I can't merge all of the files into one not corrupted .pdf file and my assumption is that there is something wrong with the rest of my .jpg files but I have no idea how to debug this issue. Every other .jpg file looks exactly the same as the one .jpg I can convert and all of them open without issues.
magick identify -verbose foobar.jpg results:

I can convert 0.jpg file to .pdf correctly but 2.jpg results in corrupted .pdf.
There are some apparent differences but I am not sure what those properties mean in the context of .jpg -> .pdf conversion


A: One thought is that someone has converted the grayscale image to color with 3 equal channels so that it IM says it has colorspace RGB. However, the JPEG colorspace tag is 2, which says it has no specific colorspace.
Properties:
    date:create: 2021-04-01T17:29:06+00:00
    date:modify: 2021-04-01T05:18:58+00:00
    exif:ExifOffset: 46
    exif:ExifVersion: 48, 50, 50, 48
    exif:PixelXDimension: 960
    exif:PixelYDimension: 1508
    exif:Software: Google
    jpeg:colorspace: 2
    jpeg:sampling-factor: 2x2,1x1,1x1

From the JPG docs
ColorSpace
0 = Bi-level 
1 = YCbCr, ITU-R BT 709, video 
2 = No color space specified 
3 = YCbCr, ITU-R BT 601-1, RGB 
4 = YCbCr, ITU-R BT 601-1, video 
8 = Gray-scale 
9 = PhotoYCC 
10 = RGB 
11 = CMY 
12 = CMYK 
13 = YCCK 
14 = CIELab

It is possible that this conflict or lack of colorspace may confuse certain viewers after the file is imbedded in a PDF vector shell.

A: Thank you @Mark Setchell for pointing me in the right direction by sharing this command:
magick identify -verbose XXX.jpg

My images are grayish so I don't know why majority of the files has sRGB colorspace but after converting colorspace to Gray I can convert them to .pdf properly (I don't see any difference when I open up my .jpgs after conversion to grayscale).
Using this command I can change colorspace to Gray:
magick 2.jpg -colorspace gray gray2.jpg

Then I can convert "grayscale" .jpgs to .pdf by simply:
magick gray2.jpg gray2.pdf


P.S.
If anyone has some better solution I will gladly accept it but if nothing shows up I am going to accept this
@fmw42
Here is a .zip file that contains

*

*20.jpg - source image

*20.pdf - corrupted pdf after running >magick 20.jpg 20.pdf

*gray20.jpg - source image converted to gray by >magick 20.jpg -colorspace gray gray20.jpg

*gray20.pdf - source image converted to .pdf after changing colorspace to gray first by >magick gray20.jpg gray20.pdf
Keep in mind that this image is from some weird manga but I have tried to pick the most normal page (it was harder than it seemed to be but this image itself is not nsfw)
